1. Field
Example embodiments relate to methods of preparing monodisperse particles, monodisperse particles prepared by using the methods, and tunable photonic crystal devices using the monodisperse particles.
2. Description of the Related Art
Photonic crystals have a lattice structure in which two or more materials having different refractive indices are regularly arranged in a two-dimensional (2D) or three-dimensional (3D) shape. Photonic crystals having a lattice structure with a photonic bandgap through which light having a predetermined or given wavelength can be intercepted or transmitted, due to periodic distribution of refractive indices of the materials. For example, when the photonic bandgap of photonic crystals is formed in a visible light band and the frequency of light incident on the photonic crystals corresponds to the photonic bandgap, 99% or more of incident light should be reflected from, the photonic crystals. Contrary to this, most of the incident light having a frequency other than the photonic bandgap of the photonic crystals is transmitted through the photonic crystals.
Technologies for applying photonic crystals to a variety of electro-optical devices, e.g., wavelength filters or display devices, by adjusting the photonic bandgap of photonic crystals have been suggested. For example, it has been reported that stop band tuning is performed by controlling effective refractive indices of materials used in forming photonic crystals. However, in such stop band tuning methods, there is little change in refractive indices, and there is a limitation in a tuning range of a stop band. Thus, it is difficult to apply photonic crystals to display devices. As another method, a method of adjusting the photonic bandgap of photonic crystals by controlling a lattice distance of photonic crystals has been suggested. There are a number of well-known methods of controlling a lattice distance of photonic crystals, e.g., a method of encapsulating photonic crystals with a polymer matrix and using a phenomenon whereby the polymer matrix swells or deswells due to oxidation/reduction according to an electrical signal of the polymer matrix and compressing/stretching the polymer matrix, and a method of using a phenomenon whereby a polymer matrix swells or deswells because the polymer matrix reacts with temperature, humidity, or chemical and biological stimuli. However, in such methods, the speed of switching color is limited because the polymer matrix swells or deswells at a relatively low speed. Thus, there is a limitation in applying photonic crystals to display devices.